1. Field of the Invention
The present invention relates to drainage systems and, in particular, to active drainage systems for removal of liquids and gases from the body of an animal, for example, from the pleural cavity of a patient following lung surgery.
2. Description of the Related Art
Early patient drainage systems, for example chest tube drainage systems, utilized a glass bottle and glass tube immersed under water. Vacuum pressure applied to the glass bottle vented fluids from the chest cavity of a patient. The degree of suction was regulated by the height of a column of water inside the glass tube. These chest tube drainage systems required substantial effort from trained personnel to set up and operate, and they required continuous monitoring of the water column and vacuum levels. The tedious initiation and labor-intensive use of such systems limited their availability to hospitals, where patients requiring active chest tube drainage remained until the active drainage was no longer required.
When the number of coronary artery bypass surgeries exploded in the early 1970""s, several new types of disposable chest tube drainage systems were introduced on the market. These drainage systems typically connect to either a central vacuum line or to a separate vacuum pump connected to an electrical outlet. While somewhat easier to operate, the availability of these systems generally remained limited to hospitals.
Also, these systems, still used today, are less than ideal for certain types of chestrelated surgeries. For example, existing chest tube drainage systems were designed primarily for cardiac surgeries, and not for pulnonary or lung-related surgeries. Since the number of lung-related surgeries is substantially less than the number of cardiac surgeries, very little research and development has been directed to the design of commercial drainage systems for lung-related surgeries or other types of medical procedures presenting recovery concerns which differ from those related to cardiac surgeries.
For example, following cardiac surgery, physicians are concerned with the precise amount of bleeding as well as the recovery of the patient""s blood which is often given back to patients. In contrast, however, during a patient""s recovery from lung surgery, a surgeon is generally more concerned about the presence and persistence of air leaks in the patient""s lung(s) than the amount of bleeding from the surgery. Such air leaks from lungs, especially emphysematous lungs, can persist for days or even weeks, and must be carefully monitored. Following lung surgery, the fluid drained from a patient is typically a mixture of blood and lymph and gases, and current protocols do not include giving that mixture back to the patient.
One problem with existing drainage systems is that the vacuum generated by a central vacuum line or an AC-powered portable suction pump can be quite powerful. To prevent injury from excessive vacuum force, existing drainage systems use pressure regulating means such as a water column or a dry pressure regulator. Despite these safety features, bodily tissue, such as lung tissue, may be injured if it is sucked against the chest tube due to excessively high vacuum power of the central vacuum line.
Another problem is that drainage systems that are now commercially available have been designed only for in-patient (hospital-based) use. Even in the hospital, existing drainage systems substantially impair patient mobility. Moreover, the complexity of these systems requires constant in-service training of nurses and technicians to operate them.
Surgical patients often require drainage treatments for extended periods of time following surgical procedures. For example, when air leak after lung surgery persists, chest tubes, which remain in the patient""s chest following the surgery, often need to be suctioned for many days. If the amount of air leak is small and the patient""s general condition is stable, such a patient may now be discharged home with a chest tube connected to a one-way valve, such as Heimlich valve. Such one-way valve systems, however, use passive drainage means, which frequently fail to prevent collapsing of the lung, and, therefore, the utility of such systems is very limited.
There is now a great need and demand in the medical community for an active portable drainage system, which will allow medically stable patients go home soon after surgery with their chest tubes continuously and safely vented during recovery. Not only would the medical expenses for these patients be markedly reduced, but also they would be permitted to recover in the more familiar and comfortable, and less stressful, environment of their own homes.
One aspect of the present invention is a portable active drainage system. The system comprises (1) a vacuum source creating a vacuum; (2) a vacuum chamber having a drainage tube port, a vacuum port and a reservoir port, the vacuum chamber connected to the vacuum source through the vacuum port to apply the vacuum to vent fluid from an animal through the drainage tube port when the drainage tube port is connected to a drainage tube extending from a location inside the animal; and (3) a reservoir having an input port connected to the reservoir port, the reservoir receiving vented liquid through the input port, the reservoir configured in combination with the vacuum source and the vacuum chamber to provide a self-contained and transportable unit. In preferred embodiments of this system, a further advantageous aspect exists wherein the vacuum chamber separates gas and liquid from the vented fluid. Another advantageous aspect of this system further comprises a flow meter indicating a flow quantity. A further advantageous aspect of the system is one wherein the flow quantity corresponds to a leak in at least one lung of the animal. Still another advantageous aspect of the system is one wherein the vacuum source includes a vacuum pump and a power source. A still further advantageous embodiment of the system is one wherein the vacuum source is substantially enclosed within a vacuum pump housing. Another advantageous aspect of the system is one wherein the power source includes at least one battery and wherein the vacuum pump operates from electrical current provided by the at least one battery. A further advantageous embodiment of the system is one wherein the power source includes a power converter converting current from a standard electrical outlet to an electrical current suitable to power said vacuum pump and wherein the power converter is configured to be connected to a standard electrical outlet. Yet another advantageous embodiment of the system is one wherein the battery is a rechargeable battery, and wherein the power source includes a battery recharger configured to charge the battery and provide current suitable to power the vacuum pump. Another advantageous embodiment of the system is one wherein the vacuum chamber includes at least one baffle separating liquid and gas from the vented fluid. In yet another advantageous embodiment, the system is one wherein the reservoir port includes a one-way valve, the one-way valve maintaining the vacuum inside the vacuum chamber during removal or replacement of the reservoir. Still another advantageous embodiment of the system is one wherein the vacuum source moves gases from the vacuum chamber into the atmosphere. A still further advantageous embodiment is one wherein the vacuum port includes a one-way valve, the one-way valve maintaining vacuum inside the vacuum chamber during an interruption in the vacuum source. In another advantageous embodiment, the system further comprises a regulating control that regulates the vacuum. A further advantageous aspect of the system is one wherein a maximum vacuum permitted by the regulating control is insufficient to injure living tissues exposed to the maximum vacuum. In yet another advantageous embodiment, the system further comprises a vacuum relief valve regulating the vacuum. In a still further advantageous embodiment, the system further comprises a tilt switch detecting tilt along at least one axis and providing a tilt signal when the amount of tilt exceeds a predetermined threshold. In a further advantageous embodiment, the system further comprises a tilt alarm responding to said tilt signal by generating an audible sound. In yet a further advantageous embodiment, the system further comprises a tilt alarm responding to the tilt signal by generating a visible indication of a tilt condition. In another advantageous embodiment, the system further comprises a second drainage tube port, wherein fluid is vented from the animal through the second drainage tube port when the second drainage tube port is connected to a second drainage tube extending from a location inside the animal.
Another aspect of the present invention is a method for draining fluid from an animal. The method comprising the steps of (1) inserting a first end of a first drainage tube into an animal; (2) connecting a second end of the first drainage tube to a first drainage tube port of an active drainage system, the animal supporting the weight of the active drainage system, the active drainage system including a source of electricity and producing vacuum from the electricity; and (3) applying the vacuum to the second end of the first drainage tube. Preferred embodiments of the method exist, and, in one advantageous aspect, the method is one wherein the animal ambulates using its natural mode of transportation during the application of the vacuum. In a further preferred embodiment, the method comprises the further step of venting fluid from the animal into the active drainage system through the first drainage tube. In another preferred embodiment, the method comprises the further step of collecting liquid from the animal in a reservoir of the active drainage system. In still another preferred embodiment, the method comprises the further step of separating gas and liquid from the vented fluid. A further advantageous aspect of the method is one wherein the animal is a human. Another advantageous embodiment of the method comprises the further steps of inserting a first end of a second drainage tube into the animal; connecting a second end of the second drainage tube to a second drainage tube port of the active drainage system; and applying vacuum to the second end of the second drainage tube. Still another advantageous embodiment of the method comprises the further steps of inserting a first end of a second drainage tube into the animal; and connecting a second end of the second drainage tube to a first drainage tube port of a second active drainage system, the animal supporting the weight of the second active drainage system.
Yet another aspect of the present invention is a method for draining fluid from an animal. The method comprises the steps of (1) inserting a first end of a first drainage tube into an animal; (2) connecting a second end of the first drainage tube to a first drainage tube port of an active drainage system, the animal supporting the weight of the active drainage system; (3) applying vacuum to the second end of the first drainage tube, the vacuum generated by the active drainage system; (4) venting fluid from the animal; and (5) separating gas and liquid from the vented fluid. Further advantageous preferred embodiments exist, and one preferred embodiment of the method comprises the further step of exhausting the gas into the atmosphere during the application of the vacuum. Another advantageous embodiment of the method comprises the further steps of tilting the active drainage system at least a predetermined number of degrees along an axis; and responding to the tilting by activating a perceivable alarm.
Still another aspect of the present invention is a method for draining fluid from a mammal. The method comprises the steps of (1) inserting a chest tube into the pleural cavity of a mammal so that a first end of the chest tube is proximate to a lung; (2) connecting a second end of the chest tube to an active drainage system; (3) applying a vacuum from the active drainage system to the chest tube; (4) regulating the vacuum to correspond to an air leak in the lung; and (5) venting fluid from a location proximate to the lung while the mammal ambulates and while the mammal supports the weight of the active drainage system. Further advantageous preferred embodiments exist, and one further advantageous preferred embodiment of the method is one comprising the further step of determining an amount of air leak in the lung with a flow meter of the active drainage system. Another advantageous embodiment of the method comprises the further step of regulating the vacuum so that it does not harm living tissue proximate to the first end of the chest tube. Another advantageous embodiment of the method is one wherein the mammal is a human.
Another aspect of the present invention is a portable active drainage system. The system comprises (1) vacuum generating means for generating a vacuum; (2) power source means for supplying an electric current to the vacuum generating means; (3) venting means for directing vacuum from the vacuum generating means to a drainage tube extending from a location inside an animal and for venting fluid from the animal; (4) separating means for separating liquid and gas from the vented fluid; (5) collection means for collecting the separated liquid; and (6) support means permitting the animal to support the weight of the portable active drainage system while ambulating.